Cathode subassembly with integrated separator for electrolytic capacitor, and method of manufacture thereof

ABSTRACT

A cathode subassembly for use in an electrolytic capacitor may include a first separator sheet including a surface having first and second regions, where the second region extends from a perimeter of the first region to a first peripheral edge of the first sheet, a second peripheral edge of a second sheet is substantially aligned with the first peripheral edge, a conductive foil is sandwiched between the first and second sheets and disposed within the first region, the first and second sheets are adhered to each other in a sealing region extending from the second region to a region of a surface of the second sheet facing the second region, and the first sheet includes at least one first recess portion at the first peripheral edge aligned with at least one second recess portion at the second peripheral edge of the second sheet.

RELATED APPLICATIONS

This Application is a continuation of U.S. patent Ser. No. 15/873,044,filed on Jan. 17, 2018, and incorporated herein in its entirety.

FIELD

The present disclosure relates generally to the field of electrolyticcapacitors and batteries.

BACKGROUND

Compact, high voltage capacitors are utilized as energy storagereservoirs in many applications, including implantable medical devices.These capacitors are required to have a high energy density, since it isdesirable to minimize the overall size of the implanted device. This isparticularly true of an Implantable Cardioverter Defibrillator (ICD),also referred to as an implantable defibrillator, since the high voltagecapacitors used to deliver the defibrillation pulse can occupy as muchas one third of the ICD volume.

Stacked electrolytic capacitors are typically constructed with aplurality of anodes and cathodes, which must be separated by a liquidabsorbent insulative material, and are impregnated by an electricallyconductive electrolyte. If the separator is not present as a line ofsight barrier between any anode and adjacent cathode, there exists adanger of physical contact, as well as electrical breakdown of anyincidental gasses present in the completed capacitor. Either of thesescenarios would result in an undesirable partial or complete dischargeevent with a high probability of device failure.

Stacked electrolytic capacitors have utilized physical features in theconstituent components of assembly with the aim of assuring precision ofphysical alignment such that the dimensions of those components leavephysical margins that assure adequate separator coverage between allanodes and cathodes. Historically, those features have included holes inthe separators, anodes, and cathodes in order to align with features onstacking fixtures when being assembled. These holes constituteundesirably lost surface area in each anode and cathode, which in turnrequires compensation either in numbers of anodes and cathodes, oroverall physical outline of those components in order to achieve a givendesign capacitance in the finished part.

The stacked alignment holes result in an undesirably larger overallfinished part than would otherwise be required. The stacked alignmentholes also create isolated cavities in the finished part which can leadto gas rich, electrolyte starved regions ripe for latent failure. Theedges of the holes or other features necessarily create more edge lengthand complexity of shape for each anode, which increases the challenge ofremoving them flaw-free from the source anode sheet material.

BRIEF SUMMARY

Device designs are presented that include a cathode subassembly forprotecting the device from unwanted discharge, and aiding in manufactureof a stacked electrolytic capacitor configuration including cathodes ofthe cathode subassemblies and anodes for use in an electrolyticcapacitor.

In accordance with an aspect of the present disclosure, a cathodesubassembly for use in an electrolytic capacitor may include a firstseparator sheet including a surface having a first region and a secondregion, wherein the second region extends from a perimeter of the firstregion to a first peripheral edge of the first separator sheet; aconductive foil; and a second separator sheet having a second peripheraledge, wherein the second peripheral edge is substantially aligned withthe first peripheral edge, and wherein the conductive foil is sandwichedbetween the first and second separator sheets and disposed within thefirst region, and wherein the first and second separator sheets areadhered to each other in a sealing region extending from the secondregion of the first separator sheet to a region of a surface of thesecond separator sheet facing the second region, and wherein the firstseparator sheet includes at least one first recessed portion at thefirst peripheral edge aligned with at least one second recessed portionat the second peripheral edge of the second separator sheet.

In accordance with an aspect of the present disclosure, a device mayinclude a conductive anode; a dielectric material disposed on a surfaceof the conductive anode; a cathode subassembly, wherein the cathodesubassembly includes: a first separator sheet including a surface havinga first region and a second region, wherein the second region extendsfrom a perimeter of the first region to a first peripheral edge of thefirst separator sheet; a cathode; and a second separator sheet having asecond peripheral edge, wherein the second peripheral edge issubstantially aligned with the first peripheral edge, and wherein thecathode is sandwiched between the first and second separator sheets anddisposed within the first region, and wherein the first and secondseparator sheets are adhered to each other in a sealing region extendingfrom the second region of the first separator sheet to a region of asurface of the second separator sheet facing the second region, andwherein the first separator sheet includes at least one first recessedportion at the first peripheral edge aligned with at least one secondrecessed portion at the second peripheral edge of the second separatorsheet; and an electrolyte disposed between the anode and the cathodesubassembly.

In accordance with an aspect of the present disclosure, a method forproducing an assembly for use in an electrolytic capacitor may include:providing a first separator sheet cell including a surface having afirst region and a second region, wherein the second region extends froma perimeter of the first region to a first sheet cell edge, and whereinthe surface of the first separator sheet cell includes adhesive materialother than on the first region; disposing a conductive foil on thesurface of the first separator sheet cell within the first region;disposing a second separator sheet portion over the first separatorsheet cell having the conductive foil within the first region, such thatthe conductive foil is sandwiched between the first separator sheet celland the second separator sheet portion; sealing the first separatorsheet cell and the second separator sheet portion to each other with theconductive foil sandwiched therebetween, in which the adhesive materialseals the first separator sheet cell with the second separator sheetportion; and cutting through the adhesive material sealing the firstseparator sheet cell with the second separator sheet portion to obtain acathode subassembly including the conductive foil sandwiched between thecut first separator sheet cell and the cut second separator sheetportion, wherein the cathode subassembly has a peripheral edge formed bya first peripheral edge of the cut first separator sheet cellsubstantially aligned with a second peripheral edge of the cut secondseparator sheet portion, wherein the cathode assembly has a sealingregion in which the adhesive material seals the cut first separatorsheet cell with the cut second separator sheet portion, in which thesealing region extends from the perimeter of the first region to thefirst peripheral edge, and wherein the first peripheral edge includes atleast one first recessed portion substantially aligned with at least onesecond recessed portion of the second peripheral edge.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a cross-section of an electrolytic capacitor orbattery.

FIG. 2 is a perspective view of a cathode subassembly, according to anembodiment of the present disclosure.

FIG. 3 is a cross-section of the cathode subassembly of FIG. 2 atcross-sectional line A-A.

FIG. 4A is an exploded, perspective view of the cathode subassembly ofFIG. 2 .

FIG. 4B is another exploded, perspective view of the cathode subassemblyof FIG. 2 .

FIG. 4C is a plan view of the cathode subassembly of FIG. 2 .

FIG. 5 is a plan view of a bulk separator roll including a plurality offirst separator sheet cells for use in manufacture of cathodesubassemblies, according to an embodiment of the present disclosure.

FIG. 6 is a plan view of a first separator sheet cell of the separatorroll of FIG. 5 , according to an embodiment of the present disclosure.

FIG. 7 is a plan view of a partially manufactured cathode subassembly,according to an embodiment of the present disclosure

FIG. 8 is a flowchart of a process for manufacture of a cathodesubassembly, according to an embodiment of the present disclosure.

FIG. 9 is a flowchart of a process for manufacture of a stackedelectrolytic capacitor configuration including a cathode subassembly,according to an embodiment of the present disclosure.

FIG. 10 is a perspective, partially exploded view of an apparatus formanufacture of a stacked electrolytic capacitor configuration includinga cathode subassembly, according to an embodiment of the presentdisclosure.

FIG. 11A is an exploded, perspective view of a portion of the apparatusof FIG. 10 .

FIG. 11B is another exploded, perspective view of a portion of theapparatus of FIG. 10 .

FIG. 12A is a perspective view of a stacked electrolytic capacitorconfiguration including cathode subassemblies, anodes, cathodes andseparator sheets, according to an embodiment of the present disclosure.

FIG. 12B is an enlarged view of a portion 12B of the stackedelectrolytic capacitor configuration of FIG. 12A.

FIG. 13A is a perspective view of a stacked electrolytic capacitorconfiguration including cathode subassemblies, anodes, cathodes andseparator sheets, at a step of manufacture according to an embodiment ofthe present disclosure.

FIG. 13B is a perspective view of the stacked electrolytic capacitorconfiguration of 13A at another step of manufacture, according to anembodiment of the present disclosure.

FIG. 13C is an enlarged view of a portion 13C of the stackedelectrolytic capacitor configuration of FIG. 13B.

DETAILED DESCRIPTION

The following detailed description of capacitor and battery designsrefers to the accompanying drawings that illustrate exemplaryembodiments consistent with these devices. Other embodiments arepossible, and modifications may be made to the embodiments within thespirit and scope of the methods and systems presented herein. Therefore,the following detailed description is not meant to limit the devicesdescribed herein. Rather, the scope of these devices is defined by theappended claims.

FIG. 1 illustrates a cross-section view of an electronic component 100.Electronic component 100 includes a housing 102 that contains aplurality of cathodes 104 alternating with a plurality of anodes 108,and separated by a plurality of separators (or spacers) 106. Each anode108 includes a dielectric material 110 on or around an outer surface ofanode 108. Dielectric material 110 may be an oxide that is thermallygrown on, or deposited onto, the surface of anode 108. A high-kdielectric material may be used for dielectric material 110. Aconductive electrolyte 112 fills the space between each of the elementswithin housing 102. Electrolyte 112 may be a polymer or liquidelectrolyte as would be understood to one skilled in the art. Exampleelectrolytes include ethylene glycol/boric acid based electrolytes andanhydrous electrolytes based on organic solvents such asdimethylformamide (DMF), dimethylacetamide (DMA), or gamma-butyrolactone(GBL). The plurality of cathodes 104 may be electrically connected to asingle, common cathode terminal, while the plurality of anodes 108 maybe similarly connected to a single, common anode terminal.

Electronic component 100 may be, for example, an electrolytic capacitoror a battery. When electronic component 100 is used as a capacitor,example materials for plurality of cathodes 104 include aluminum,titanium, stainless steel, while example materials for plurality ofanodes 108 include aluminum and tantalum. When electronic component 100is used as a battery, example materials for plurality of cathodes 104include silver vanadium oxide, carbon fluoride, magnesium oxide, or anycombination thereof, while example materials for plurality of anodes 108include lithium metal.

Spacer 106 may be provided to maintain a given separation between eachcathode 104 and an adjacent anode 108 within housing 102. Additionally,spacer 106 may be provided to prevent arcing between cathode 104 andanode 108 in spaces where dielectric 110 may be very thin ornonexistent, and/or where a void within electrolyte 112 exists betweencathode 104 and anode 108.

Aligning each cathode 104, spacer 106, and anode 108 together in a stackis typically performed using physical features on each element that fittogether (such as a peg-in-hole arrangement). As discussed above, thisreduces the total usable surface area, which in turn reduces the overallenergy density of electronic component 100.

It should be understood that the various elements and dimensions ofelectronic component 100 are not drawn to scale. Although each ofcathode 104, separator 106, and anode 108 are illustrated as being apartfrom one another for the convenience of illustration and labeling, itwould be understood by one skilled in the art that such elements mayalso be stacked together in close physical contact with one another.

FIGS. 2, 3, 4A, 4B and 4C illustrate a cathode subassembly 200,according to an embodiment of the present disclosure. Cathodesubassembly 200 may include a cathode 202 sandwiched between twoseparator sheets 204 and 206, where the cathode 202 may be enclosed bythe sheets 204, 206 except at a terminal or cathode tail 228 of thecathode 202 which extends out from the sheets 204, 206 so as not to becovered by the sheets 204, 206. Separator sheet 204 may be disposedacross one surface of cathode 202, while separator sheet 206 may bedisposed across the opposite surface of cathode 202. The separatorsheets 204 and 206 may be sealed to each other at a sealing region 208of the subassembly 200 which is at an outer periphery of the sheets 204and 206. The sealing region 208 may surround the entirety of an outerperiphery of the cathode 202, except for a portion of the outerperiphery of the cathode 202 forming the cathode tail 228. The integralcombination of the cathode sealed in a pocket between the two separatorsheets substantially eliminates concern of contact between the cathodeof the combination and other external electrodes. The cathodesubassembly, thus, may be utilized in a stacked electrolytic capacitorconfiguration, as described below, without concern that the cathodetherein may contact other external components resulting in a short, ormay be or become improperly positioned, such as may occur due tomisalignment of components during manufacture and handling of thestacked electrolytic capacitor configuration, to allow for arc dischargesuch as with an adjacent anode.

Cathode 202 may be commonly formed from a metal foil or plate, such asaluminum, titanium or stainless steel. Cathode 202 may be anyelectrically conductive material that can be formed into a uniform, thinsheet. The cathode tail 228 may be an extension of the material ofcathode 202, or be a different material that is bonded to cathode 202.As used herein, the terms “foil,” “sheet,” and “plate” are usedinterchangeably to refer to a thin, planar material.

Each separator sheet 204 and 206 may include a high density Kraft paper.Other example materials include woven textiles made of one or acomposite of several nonconductive fibers such as aramid, polyolefin,polyamide, polytetrafluoroethylene, polypropylene, and glass. Separatorsheets 204 and 206 should be porous enough such that an electrolyte canpenetrate through each separator sheet 204 and 206. Any insulatingmaterial that can be formed into a uniform, thin sheet with a porousstructure may be used for separator sheet 204 and 206. The insulatingmaterial preferably shows no dissolution or shrinkage when introduced tothe electrolyte. Similarly, the insulating material preferably does notelute any chemicals when introduced to the electrolyte that would damageany part of a battery device including the cathode subassembly over time(e.g., corrosives or, in the case of aluminum electrolytic capacitors,halides.)

Referring to FIGS. 2, 3, 4A, 4B and 4C, where FIG. 4C includes dashedlines to indicate regions of a surface 210 of the sheet 204 as describedbelow, the sheet 204 is bounded by a peripheral edge 220 including aperipheral edge portion 220 a, and the sheet 206 is bounded by aperipheral edge 224 including a peripheral edge portion 224 a. Thecathode tail 228 extends out from the sheets 204, 206 at the edgeportions 220 a, 224 a. The peripheral edges 220 and 224 are in alignmentwith each other and together form a peripheral edge of the subassembly200, except at the portions 220 a, 224 a. The surface 210 of the sheet204 may include a first region 214 and a second region 216, where thesecond region 216 surrounds the first region 214 except at a portion 274of the first region 214 from which the cathode tail 228 extends out fromthe sheets 202, 204. The edge portions 220 a, 224 a are aligned witheach other and form, at the portion 274, an outermost periphery of thesheets 202, 204 from which the cathode tail extends out from the sheets202, 204. The first region 214 is bounded by the edge portion 220 a anda perimeter 218 that extends, following a shape of the peripheral edge220, from one end of the edge portion 220 a to an opposite end of theedge portion 220 a of the sheet 204. The second region 216 extends fromthe perimeter 218 of the first region 214 to the peripheral edge 220 ofthe sheet 204. The second region 216 is not present at the peripheraledge portion 220 a.

Referring to FIGS. 2, 3, 4A, 4B and 4C, the sealing region 208 may bealigned with the second region 216, extending from the perimeter 218 tothe peripheral edge 220. In addition, the sealing region 208 may includeportions of the surface 212 of the sheet 206 which extend from theperipheral edge 224 of the sheet 206 and confront the second region 216.In one embodiment, the sealing region 208 may extend along an entiretyof the peripheral edges 220, 224 of the sheets 204, 206 of thesubassembly 200, except at the edge portions 220 a, 224 a.

The perimeter 218 of the first region 214 may have a contourcorresponding to a shape of the portion of the peripheral edge 226 ofthe cathode 202 which is positioned within the region 214 between thesheets 204, 206. In some embodiments, the perimeter 218 may have anyshape of any complexity, where the shape of the perimeter 218corresponds to a shape of the outermost periphery of the portion of thecathode disposed within the first region 214.

Referring to FIGS. 3 and 4A, adhesive material 222 may be disposed inthe sealing region 208. In one embodiment, at least a portion or theentirety of the surface 210 in the second region 216 extending from theperimeter 218 to the peripheral edge 220 may include adhesive material222. The surface 210 in the first region 214 does not include adhesivematerial thereon. In the sealing region 208, the adhesive material 222may extend from the surface 210 to a portion of the surface 212 of thesheet 206 confronting the second region 216. In some embodiments, theadhesive material 222 may extend to the peripheral edge 224 of the sheet206.

In one embodiment, referring to FIGS. 3, 4A and 4B, the adhesivematerial 222 may be in the form of a strip 222 a in the second region216 which at least partially or completely follows the perimeter 218,and is disposed on the surface 210 extending from the perimeter 218 tothe peripheral edge 220.

In one embodiment, the perimeter 218 may be spaced, from facing portionsof the peripheral edge 220, a minimum distance sufficient to providesatisfactory permanent sealing of the sheets to each other in thesealing region 208 by the adhesive material 222 in the sealing region208. In some embodiments, the perimeter 218 may be spaced asubstantially same distance from the facing portions of the edge 220along the entire length of the perimeter 218, and in one embodiment suchspacing is about 0.02 inches

According to an embodiment, the distance from the perimeter 218 to thefacing portion of the peripheral edge of the subassembly 200 may beselected such that the distance is small enough to minimize the overallfootprint of the portions of the separator sheets extending away fromthe peripheral edge 226 of the cathode, but large enough to ensuremechanical robustness and long-time reliability of the seal between theseparator sheets in the sealing region.

Example adhesive materials may include UV curable polymers, acrylicpolymers, silicones, polyurethanes, polysulfides and cyanoacrylates.According to an embodiment, the adhesive material does not dissolve inthe presence of an electrolyte and does not elute any chemicals whenintroduced to the electrolyte that would damage any part of a batterydevice over time (e.g., corrosives or, in the case of aluminumelectrolytic capacitors, halides). The adhesive material is selected andconfigured to provide a permanent bond between separator sheet 204 andseparator sheet 206 in the sealing region 208, according to anembodiment.

In one embodiment, a thickness of the adhesive material 222 between thesheets 204 and 206 may be equal to or less than a thickness of thecathode 202. By maintaining the thickness of the adhesive material notmore than the thickness of the cathode, a high packaging efficiency ofthe cathode subassembly, which may be included with other componentssuch as anodes, cathodes, separator sheets and additional cathodesubassemblies in a stacked electrolytic capacitor configuration asdescribed below, may be achieved.

Still referring to FIG. 4C, in one embodiment, the cathode 202 may havea shape and size such that, when the cathode 202 is disposed in thefirst region 214, the peripheral edge 226 of the cathode 202 is alignedwith dashed line 230 in the first region 214. The line 230 is interiorto and has a same or substantially the same configuration as theperimeter 218, and may be uniformly spaced about 0.02 inches from theperimeter 218. The portion of the surface 210 extending from theperimeter 218 to the line 230 defines a margin assembly region 232. Themargin assembly region 232 may allow for manufacturing tolerance whenthe cathode 202 is disposed upon the surface 210, such as by anautomated process or manually during manufacture of the subassembly 200as discussed in detail below, such that the cathode 202 is disposed onlywithin the region 214 and does not contact adhesive material 222 in thesecond region 216.

In one embodiment, a size of the portion of the cathode 202 disposed inthe first region 214 is slightly smaller than the first region 214, suchthat the cathode 202, except for the cathode tail 228, may fit entirelywithin the first region 214 and be spaced from the perimeter 218. Inanother embodiment, the cathode 202 may have a shape and size at theperipheral edge 226, such that the edge 226 is aligned or substantiallyaligned with the perimeter 218 when the cathode 202 is disposed in thefirst region 214.

In addition, referring to FIG. 2 , in one embodiment, the cathode tail228 may include apertures 229 extending entirely therethrough. Theapertures 229 may provide additional means for aligning individualcathode subassemblies 200 with each other and other components duringmanufacture of a stacked electrolytic capacitor configuration, asdescribed below.

Further, the peripheral edges 220 and 224 may be configured to includeone or more recessed portions 240 and 242, respectively, which are otherthan at the edge portions 220 a and 224 a, and which are aligned witheach other. The recessed portions 240 and 242 desirably have anidentical or substantially identical configuration, and each alignedpair of recessed portions 240, 242 together define an alignment regionat the peripheral edge of the subassembly 200. The alignment region, forexample, may be arcuate, semicircular or oblong, and may have a shapecorresponding to an exterior surface of an alignment element, such as analignment pin, used in the manufacture of a stacked electrolyticcapacitor configuration including the cathode subassembly, as describedbelow. Referring to FIGS. 2 and 4C, the perimeter 218 of the firstregion 214, the line 230 which defines an interior boundary of themargin assembly region 232 and the peripheral edge 226 of the cathode202 may, at the alignment region(s) defined by the pair(s) of recessedportions 240, 242, have a shape which is similar or identical to theshape of the alignment region(s). In some embodiments, the perimeter 218of the first region 214 and the peripheral edge of the portion of thecathode within the first region 214 may have a shape corresponding tothe shape of the peripheral edge of the subassembly 200, except at theportion of the peripheral edge of the subassembly 200 defined by thecathode tail 228.

In one embodiment, referring to FIG. 4C, alignment regions of thesubassembly 200 may be positioned on a side 250 of the subassembly 200from which the cathode tail 228 extends outwardly, and also on a side252 of the subassembly 200 opposing the side 250. For example, thealignment regions may include, at the side 250, an alignment region ateach end of the edge portions 220 a, 224 a, and another alignment regionat the side 252 positioned opposite the cathode tail 228. It is to beunderstood that the alignment regions may be positioned anywhere alongthe peripheral edge of the subassembly 200, except at the portion of theperipheral edge of the subassembly 200 corresponding to a peripheraledge of the cathode tail 228.

Referring to FIGS. 5 and 6 , in one embodiment, the sheet 204 of thesubassembly 200 may be obtained from a sheet roll 205 including aplurality of sheet cells 204 a. Each sheet cell 204 a may be square- orrectangularly-shaped with outer peripheral edges 260 a, 260 b, 260 c and260 d, and include regions 262 and 264. The region 262 may extend fromthe edge 260 a to a perimeter 227 of the region 262, where the perimeter227 extends from the edge 260 b to the edge 260 d. The region 264 may bedefined by the perimeter 227, the edge 260 c and the portions of theedges 260 b and 260 d extending from the perimeter 227 to the edge 260c. Adhesive material 222 may be disposed on surface 268 of the sheetcell 204 a within the region 264, except in first region 214 of thesurface 268 which is within the interior of the region 264. The firstregion 214 of the sheet cell 204 a may have same size and shape as thefirst region 214 of the subassembly 200. The first region 214 of thesurface of the sheet cell 204 a, on which the cathode 202 is disposedsuch that the cathode 202 does not extend beyond perimeter 218 of thefirst region 214 (see FIG. 7 ), does not include adhesive material 222.

In some embodiments, the adhesive material may be provided on theseparator sheet roll at the above described locations of sheet cells by,for example, selective application. In another embodiment, the adhesivematerial may be provided at the selected locations on sheet cells 204 a,by use of a pressure sensitive peel release liner that provides forselective removal of portions of an adhesive laminate that covers anentirety of a separator sheet roll.

In addition, in some embodiments, referring to FIG. 6 , the sheet cell204 a may include apertures 270 extending entirely therethrough, in aportion of the region 264 between the region 262 and the first region214. The apertures 270 may provide means for holding and moving the roll205, or individual sheet cells 204 a of the roll 205, during a processof automated manufacture of the cathode subassembly.

In one embodiment, as shown in FIG. 6 , an edge portion 260 c′ of edge260 c may define a peripheral edge of the first region 214 which extendsbetween opposing portions 218 a and 218 b of the perimeter 218 thatterminate at respective ends of the edge portion 260 c′. The perimeterportions 218 a and 218 b are spaced from each other so as to define theregion 274 within the region 214. The edge portion 260 c′ corresponds tothe edge portion 220 a of the sheet 204 of the subassembly 200 that isformed from the sheet cell 204 a. As discussed above, and referring toFIGS. 2 and 7 , the cathode tail 228 of the cathode may be disposedpartially in the region 274 and extend out from the sheets 204, 206 atthe region 274.

In one embodiment, referring to FIGS. 2, 4A, 4B, 4C, 6 and 7 , theregion 274 may be configured to have a size and shape, such that theregion 274 of the sheet 202, together with a portion of the sheet 206aligned with the region 274, forms a protruding or extended separatorsheet portion 248 of the subassembly 200 that overlies a portion ofopposing surfaces 228 a, 228 b of the cathode tail 228. In theillustrated embodiment, referring to FIG. 6 , portions 218 c and 218 dof the perimeter 218 may extend from the perimeter portions 218 a and218 b, respectively, substantially parallel to the edges 260 d and 260 band be spaced from portions of the edge 260 c that the perimeterportions 218 c, 218 d confront. The region 274 may be bounded by theedge portion 260 c′, which is co-linear with the portions of the edge260 c that the perimeter portions 218 c, 218 d confront. In oneembodiment, referring to FIGS. 2 and 6 , a line co-linear with each ofthe edge portion 220 a (edge portion 260 c′) and the edge portion 224 amay be spaced a distance D from adjacent portions of the peripheral edgeof the subassembly 200, for example, the portions of the edges 220 and224 that respectively confront the perimeter portions 218 c, 218 d, suchthat the extended separator sheet portion 248 protrudes a distance D inrelation to adjacent portions of the peripheral edge of the subassembly200. For example, the extended separator sheet portion 248 may projectaway from adjacent portions of the peripheral edge of the subassembly200 a distance D in a direction substantially orthogonal to the adjacentportions of the peripheral edge of the subassembly 200 which confrontthe perimeter portions 218 c, 218 d, respectively, such that aperipheral edge 249 (edge portions 220 a, 224 a) of the extendedseparator sheet portion 248, at a furthest projecting point of theportion 248, protrudes, relative to the adjacent portions of theperipheral edge of the subassembly 200, a distance D in a directionsubstantially orthogonal to the adjacent portions of the peripheral edgeof the subassembly 200. The extended separator sheet portion 248 of thesubassembly 200 may advantageously avoid potential line of sight arcingdischarge and contact between the portion of the cathode tail extendingfrom the cathode subassembly and an anode plate arranged in a stackedelectrolytic capacitor configuration adjacent or near to the cathodesubassembly, during manufacture of a stacked electrolytic capacitorconfiguration as described below.

Flowchart of FIG. 8 illustrates a process 600 for manufacture of acathode subassembly, as described above with reference to FIGS. 2, 3,4A, 4C, 5, 6 and 7 . The process advantageously may repeatedly obtain aperipheral edge of a cathode subassembly, which is formed from alignedperipheral edges 220, 224 of the sheets 202, 204 as described above,within design constraint margins of about +/−0.01 to 0.002 inches.Accordingly, a stacked electrolytic capacitor configuration, whichincludes the cathode subassemblies of the present disclosure and othercomponents including anodes, cathodes and separator sheets, may bemanufactured to have a composite peripheral edge which is within designconstraint margins of about +/−0.01 to 0.002 inches. The process 600 maybe performed using an automated assembly machine, or alternativelymanually.

Referring to FIG. 8 , in block 602, a first separator sheet roll 205,such as illustrated in FIGS. 5-6 , including a plurality of firstseparator sheet cells 204 a, each having the features as describedabove, may be provided, for example, on a conveyor belt of an automatedassembly machine. The roll 205 may be provided on the conveyor belt withthe surface 268 including adhesive material 222 selectively disposedthereon exposed, and the apertures 270 of the respective sheet cells 204a may provide for holding and locating the roll 205 on the conveyorbelt.

In block 604, a roll of cathode foil may be supplied to the assemblymachine, and then a cathode 202 may be cut therefrom, with a laser or bydie cutting as conventional, such that a shape of an outer peripheraledge of the cathode 202 corresponds to a shape of the perimeter 218 ofthe first region 214. In one embodiment, the cathode may be cut suchthat the portion of its outer peripheral edge to be disposed in thefirst region 214 substantially corresponds or is identical in size andshape to line 230 defining the margin assembly region 232, as shown inFIG. 4C. Further, in block 604 the cathode 202 may be placed on one ofthe separator sheet cells 204 a within the region 214, such that noportion of the cathode extends beyond the perimeter 218 and, thus, thecathode is not in contact with the adhesive material 222 in the region264 surrounding the perimeter 218.

In one embodiment, the cathode may be cut to a size and shape such thatthe cathode fits entirely within the region interior to the assemblymargin region 232, as shown in FIG. 7 .

In one embodiment, the adhesive material may be colored, for example,with a dye, such that a vision system of the assembly machine may, basedon the color of the adhesive material, readily align the cathode withthe region 214, and desirably provide that the cathode is placed withinthe region 214 interior to the assembly margin region 232.

In block 606, a roll of second separator material (“second separatorroll”), which is formed only from separator material and does notinclude adhesive material, may be provided for use in formation of theseparator sheet 206 of the cathode subassembly. The second separatorroll may be fed into the assembly machine, and suitably manipulatedwithin the machine such that the second separator roll is placed overthe exposed surface of the first separator roll 205 containing cathodesplaced respectively within regions 214 of the sheet cells 204 a. Thesecond separator roll may then be pressed against the roll 205 with thecathodes thereon, to activate pressure activated adhesive material 222on the roll 205. By activation of the adhesive material, a seal may becreated between surface portions of the separator sheet cells 204 a atwhich the adhesive material is disposed and portions of the secondseparator roll overlying the adhesive material on the sheet cells 204 a.For each sheet cell 204 a, a cathode is within the region 214, and issealed between the sheet cell 204 a and the overlying portion of thesheet 206 except at the edge portion 260 c′ of the sheet cell 204 a.

In block 608, cutting may be performed through each of the sheet cell204 a/cathode/second separator roll combinations as sealed in block 606,by use of a laser, die, mechanical shearing, cleaving or the like, toobtain individual cathode subassemblies 200 having an outer peripherywhich is sealed except at the portion of the periphery of thesubassembly 200 corresponding to the cathode tail 228 that extends outfrom the sheets 202, 204, as shown in FIG. 2 . Referring to FIG. 3 , thesealed portion of the outer periphery of the cathode subassembly 200 maybe formed by edges 220 and 224 aligned with each other, except at theedge portions 220 a, 224 a. As discussed above, the cathode tail 228 isdisposed in the region 274 and extends away from the sheets 202, 204 atthe aligned edge portions 220 a, 224 a. At other than the portions 220a, 224 a, the edges 220, 224 may be spaced about at least 0.020 inchesfrom the perimeter 218 by the sealing region 208 of the cathodesubassembly, which extends from the perimeter 218 to the edges 220 and224.

In block 610, each cathode subassembly as obtained in block 608 may beindividually tested to insure a satisfactory seal in the sealing region.For example, the testing may be performed by disposing the cathodesubassembly between two conductive plates under pressure and applying apredetermined high potential voltage (“withstand voltage”) to insurethat there is no arcing or other defect noticed. For example, awithstand voltage of 600 volts may be applied during testing of thesubassembly, to insure that the subassembly may operate without failurewhen included as part of a stacked electrolytic capacitor configurationin a capacitor having a 450 Volt working voltage specification.

The testing of the individual cathode subassemblies following theirmanufacture may advantageously improve yield and reduce waste ofresources in the manufacture of stacked electrolytic capacitorconfigurations which include the cathode subassemblies. In particular,by performing testing of only the cathode subassembly before thesubassembly is assembled into a stack with other components, the need todiscard the entirety of the components of the stack, such as when acathode subassembly in the stack has a defect and causes the entirecompleted stack to fail testing following manufacture of the stack, maybe avoided. Thus, based on manufacture of a stack including cathodesubassemblies according to the present disclosure, a high degree ofcertainty may be obtained that the stack would perform satisfactorily asan electrolytic capacitor, based on testing of the individual cathodesubassemblies before same are included in a stack.

Further, the substantially sealed, integrated structure of the cathodesubassembly completely or almost completely eliminates the possibilityof line of sight arc discharge or contact between anodes, and thecathodes within cathode subassemblies, in a completely manufacturedstacked electrolytic capacitor configuration, because the cathodes,except for the cathode tail, are disposed within an enclosure or pocketformed by the first and second separator sheets. The pocket in which thecathode in the cathode subassembly is disposed avoids the need tomanufacture a stacked electrolytic capacitor configuration in accordancewith a design constraint requiring offset of cathodes from adjacentanodes, because the sheets forming the integral subassembly serve as aninsulative barrier between edge portions of anode plates in the stackand the cathodes in the adjacent cathode subassemblies, therebysubstantially or completely eliminating the potential of contact or lineof sight arc discharge therebetween.

In addition, the portion of the sheet 202 at region 274 and theoverlying portion of the sheet 204, which form an extended sheet portionof the subassembly 200, are configured to avoid line of sight arcdischarge and contact between edge portions of an anode plate in a stackand exposed portions of cathode tails which extend away from the edgeportions 220 a, 224 a of the cathode subassemblies included in the stackwith the anode plate. Thus, design requirements for offset of a cathodefrom an anode, such as the peripheral edge of the cathode beingretracted by a predetermined amount from the peripheral edge of anoverlying or underlying separator sheet and an anode in a stack, and aminimum line of sight barrier for a stack, such as 0.070 inches for aline of sight barrier from a cathode peripheral edge to an anodeperipheral edge, may be eliminated or relaxed, by providing cathodes inthe stack which are integrated within cathode subassemblies inaccordance with the present disclosure.

Advantageously, according to the present disclosure, a single integratedassembly of the cathode and a separator may be obtained in the form acathode subassembly, in which the cathode is sealed therein by the twoseparator sheets and adhesive material as described above, whichincludes an electrolyte permeable physical barrier to access surfaces ofthe cathode, which has a substantially uniform thickness and thicknessnot exceeding a combined thickness of the cathode and the two separatorsheets, which includes alignment regions at the peripheral edge to easemanufacture in a stacked electrolytic capacitor configuration with othercomponents included in the stack, and where the cathode is sufficientlysealed by the separator sheets and adhesive combination to electricallysupport a design voltage operation for the cathode, such as whenincluded in an electrolytic capacitor.

Flowchart of FIG. 9 illustrates a process 700 for manufacture of astacked electrolytic capacitor configuration including one or morecathode subassemblies of the present disclosure, such as manufacturedaccording to the process 600, in accordance with an embodiment of thepresent disclosure.

The process 700 may be performed, for example, using a stack assemblyapparatus 1000 as illustrated in FIGS. 10, 11A and 11B. Referring toFIGS. 10, 11A and 11B, the stack assembly apparatus 1000 may include anarm 1002 interconnecting a support base 1004 and a stacking fixture orbase plate 1006. The base plate 1006 may have a peripheral edge 1008including recesses 1010 configured to receive alignment elements or pins1012 that extend from an alignment block 1013, which is at a bottomsurface of the base plate, to above a surface 1014 of the base plate.The alignment block 1013 may further include cathode tail alignment pins1022, which extend above the surface 1014 of the base plate. Thealignment elements or pins 1012 may be configured such that an externalsurface portion thereof facing an interior region of the base plate 1006has a shape corresponding to a shape of alignment regions at theperipheral edge of the cathode subassembly, as well as other alignmentregions of components to be included in a stack with the cathodesubassembly. The pins 1012 may be positioned to contact respectivelycorresponding alignment regions of the cathode subassembly, and alsoalignment regions respectively of other components that may be includedin the stack. In addition, the pins 1022 may be configured andpositioned to extend through apertures 229 of the cathode tail of thesubassembly 200 when the subassembly 200 is included in a stack formedon the base plate 1006.

Referring to FIG. 9 , in block 702, cathode subassemblies, such as thosethat pass the testing of block 610 as described above, may be placed ina hopper for assembly into a stack using the apparatus 1000, oralternatively for use in a manual process of stack assembly.

In block 704, a cathode subassembly from the hopper may be disposed onthe base plate 1006 of a stack assembly apparatus 1000, such as byoperation of a robotic assembly device. In particular, the cathodesubassembly may be arranged on the base plate 1006 such that thealignment regions are respectively aligned with corresponding alignmentelements 1012 which contact the peripheral edge of the cathodesubassembly at the portions thereof including the alignment regions. Thealignment elements 1012 may provide for precise self-alignment of theperipheral edge of a cathode subassembly with the peripheral edge ofother cathode subassemblies and also peripheral edges of anode plates,such as when each of such components is placed one over the other toform a stack. In addition, the apertures 229 in the cathode tails mayreceive the alignment pins 1022 therethrough, which may further providefor self-alignment of the subassemblies 200 in the stack.

In block 706, an electrode stack may be created by adding one or moreanodes, cathodes, separator sheets and cathode subassemblies one overthe other, such as on top of a cathode initially disposed directly onthe surface 1006 of the base plate. The stack may include any number ofanodes, in any desired arrangement with the respect to the cathodesubassemblies. In one embodiment, the anode may be an etched foil havingan outer periphery having the same configuration as the peripheral edgeof the cathode subassembly. The alignment regions of the cathodesubassemblies, and similar and corresponding alignment regions that maybe provided at the peripheral edge of an anode, may provide forself-alignment of components included in a stack. Further, based on thecreation of a stack including the cathode subassemblies together withmultiple anodes aligned with one another by the alignment regions,peripheral edge tolerances for the stack may be about +/−0.001 to 0.002inches. With such tolerances in manufacture of a stack according to thepresent disclosure, a high packaging efficiency may be obtained foranodes included in the stack, because an anode having an increasedfunctional surface area may be placed within a same volume of a stack.

In one embodiment, the permanent seal in the sealing region at theperipheral edge of the cathode subassembly may permit that the line ofsight design constraint at the peripheral edge of a stacked electrolyticconfiguration including the cathode subassembly is reduced by more than50% relative to the line of sight design constraint for a peripheraledge of a stack containing individual cathodes whose respective edgesare not surrounded by sealed sheet material as in the presentdisclosure.

Referring again to FIG. 9 , in block 708, after a desired stack ofanodes and cathode subassemblies in alignment with one another at therespective peripheral edges is formed in block 706, one or more clamps1016 may be used to hold the stack together and avoid the components ofthe stack from becoming misaligned before the stack is placed, forexample, in a case of a battery. The clamp 1016 may include a topclamping surface 1017A and a bottom clamping surface 1017B. The surface1017B may be positioned at the bottom surface of the base plate, and thetamp 1015 may then be positioned on top of the stack with the surface1017A positioned in a recess 1015A of the tamp 1015, such that the stackis held fixed in position between the tamp 1015 and the surface 1014 ofthe base plate and the components of the stack are not permitted to moveand, thus, become misaligned with other components in the stack. The useof multiple clamps 1016 advantageously allows uniform pressure to beapplied to the stack at multiple points to insure equal compressionwithin the stack, which also improves packaging efficiency for thestack.

In block 710, tape or an external boot may be applied to maintain thealigned arrangement of the elements of the stack, whose arrangement isheld fixed by the clamps 1016 under pressure. Then, the clamps may besuitably removed and a stacked electrolytic capacitor configuration,with the alignment of cathode subassemblies and anodes maintained by thetape, may undergo further manufacturing processing.

In one embodiment, referring to FIGS. 12A and 12B, an electrolyticcapacitor configuration or stack 2000 obtained in block 710 may includea cathode 2002 at each of the top and bottom of the stack 2000, aseparator sheet 2004 adjacent an interior surface of each of the top andbottom cathodes 2002 in the stack, and several sets of multiple anodes2006 and several cathode subassemblies 200. The sets of anodes may bebetween a cathode 2002 and cathode subassembly 200, or between adjacentcathode assemblies 200. Each component in the stack may have alignmentregions at the outermost peripheral edge thereof having a same shape andsize as the alignment regions of the cathode subassembly, to provide forself-alignment of all components in the stack.

Referring to FIGS. 13A, 13B and 13C, in further steps of manufacture ofa stacked electrolytic capacitor configuration according to the presentdisclosure, a stack, such as the stack 2000 of FIGS. 12A and 12B, may,by automatic or manual means, be configured to fit into a batterydevice, by joining cathode tails 2028 of the cathodes 2002 and cathodetails 228 of the subassemblies 200 to one another. Referring to FIG. 9 ,in block 712, a single cathode terminal 2018 may be formed from thecathode tails 2028 and 228, by compressing the cathode tails together atone end of the stack and then bending the cathode tails towards anadjacent peripheral edge of the stack 2000 and into contact with thecathode 2002 at the other end of the stack, and then welding the cathodetails of the stack 2000 together. When the cathode tails are beingcompressed together at one end of the stack, and when the cathode tailsare in an assembled positioned, welded together and extending along theperipheral edge of the stack to form the terminal 2018, the portion ofthe sheets 202, 204 of the subassemblies 200 at the region 274 mayprovide a barrier that avoids contact, and maintains a minimum line ofsight, between edges of the anodes 2004 and the exposed surfaces of thecathode tails, so as to avoid arc discharge or shorting between theformer and latter. The region 274, as discussed above, may be configuredto have a size and shape such that the extended separator sheet portionof each of the cathode subassemblies in a stack create a line of sightand contact barrier in view of expected bending of cathode tails duringmanufacture of a stack. After the cathode tails are welded together, thestack may be placed into a battery device.

Advantageously, the present disclosure may provide for manufacture of astacked electrolytic capacitor configuration whose components areself-aligned, without the use of complex internal mechanical features ofalignment within an interior region of components of the stack, such asanode or cathodes, which may compromise performance, because thefunctional surface area of the components is replaced by alignmentfeatures, such as apertures in the functional areas. Further, thepresent disclosure of the cathode subassembly improves manufacturabilityof a completed part of an electrolytic capacitor and increases long-termreliability, based on the inherent elimination of failures resultingfrom misalignment of components of a stack.

In addition, the present disclosure of the cathode subassembly mayprovide greater efficiency and lower costs in manufacture of anelectrode stack, because an individual element of a separator sheet isnot added to the stack for each cathode in the stack during manufactureof the stack. Instead, according to the present disclosure, the stackmay be formed by arranging the elements of the cathode subassemblies andanodes one over the other between top and bottom cathode and separatorsheets pairs, such as in the stack 2000, without providing additionalseparator sheets, which simplifies manufacturing process controls andalso the number of elements, such as robotic elements, required tomanufacture an electrode stack.

Although the disclosure herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent disclosure. It is therefore to be understood that numerousmodifications may be made to the illustrative embodiments and that otherarrangements may be devised without departing from the spirit and scopeof the present disclosure as defined by the appended claims.

The invention claimed is:
 1. A device comprising: a conductive anode; adielectric material disposed on a surface of the conductive anode; acathode subassembly, wherein the cathode subassembly includes: a firstseparator sheet including a surface having a first region and a secondregion, wherein the second region extends from a perimeter of the firstregion to a first peripheral edge of the first separator sheet; acathode; and a second separator sheet having a second peripheral edge,wherein the second peripheral edge is substantially aligned with thefirst peripheral edge, and wherein the cathode is sandwiched between thefirst and second separator sheets and disposed within the first region,and wherein the first and second separator sheets are adhered to eachother in a sealing region extending from the second region of the firstseparator sheet to a region of a surface of the second separator sheetfacing the second region, and wherein the first separator sheet includesat least one first recessed portion at the first peripheral edge alignedwith at least one second recessed portion at the second peripheral edgeof the second separator sheet; and an electrolyte disposed between theanode and the cathode subassembly, wherein the first and secondperipheral edges respectively of the first and second separator sheetsare aligned with a peripheral edge of the anode.
 2. The device of claim1 wherein the substantial alignment of the second peripheral edge withthe first peripheral edge is such that the first peripheral edge iswithin +/−0.05 to 0.002 inches of the second peripheral edge.
 3. Thedevice of claim 1, wherein the first and second peripheral edges of thefirst and second separator sheets have the same shape as the peripheraledge of the anode.
 4. The device of claim 1, further comprising: aplurality of conductive anodes arranged in a stack formation with thecathode subassembly.
 5. The device of claim 1, wherein the device is anelectrolytic capacitor.
 6. The device of claim 1, wherein the first andsecond separator sheets are permeable to the electrolyte.
 7. The deviceof claim 1, wherein the anode includes an anode recessed portion at theperipheral edge of the anode, and the anode recessed portion, the firstrecessed portion, and the second recessed portion being aligned.
 8. Thedevice of claim 1, wherein the peripheral edge of the anode is retractedfrom the first peripheral edge of the first separator sheet.
 9. Thedevice of claim 1, wherein the anode includes an anode recessed portionat the peripheral edge of the anode, a peripheral edge of the cathodeincludes a third recessed portion, and the anode recessed portion, thefirst recessed portion, the second recessed portion, and the thirdrecessed portion are aligned.
 10. The device of claim 9, wherein analignment element is received in the anode recessed portion, the firstrecessed portion, the second recessed portion, and the third recessedportion.
 11. The device of claim 10, wherein a portion of the sealingregion received in an interior of the third recessed portion is betweenthe alignment element and the third recessed portion.
 12. The device ofclaim 1, wherein the cathode includes a cathode tail that extendsthrough the sealing region and an aperture extends through the cathodetail.
 13. The device of claim 12, wherein an alignment element isreceived in the aperture.
 14. The device of claim 13, wherein thecathode is one of multiple cathodes included in the device, each of thecathodes including a cathode tail with the aperture extending throughthe cathode tail, the alignment element being received in each of theapertures.
 15. The device of claim 13, wherein a peripheral edge of thecathode is spaced apart from the sealing region.
 16. The device of claim1, wherein the cathode includes a cathode tail that extends through thesealing region, a peripheral edge of the cathode includes multiple thirdrecessed portions and the sealing region is positioned in an interior ofeach of the third recessed portions, and the tail is positioned betweentwo of the third recessed portions.
 17. The device of claim 16, whereinthe tail is positioned between the third recessed portions such that aperipheral edge of the tail is continuous with the third recessedportions.
 18. A device, comprising: a conductive anode; a dielectricmaterial disposed on a surface of the conductive anode; a cathodesubassembly, wherein the cathode subassembly includes: a first separatorsheet including a surface having a first region and a second region,wherein the second region extends from a perimeter of the first regionto a first peripheral edge of the first separator sheet; a cathode; anda second separator sheet having a second peripheral edge, wherein thesecond peripheral edge is substantially aligned with the firstperipheral edge, and wherein the cathode is sandwiched between the firstand second separator sheets and disposed within the first region, andwherein the first and second separator sheets are adhered to each otherin a sealing region extending from the second region of the firstseparator sheet to a region of a surface of the second separator sheetfacing the second region, and wherein the first separator sheet includesat least one first recessed portion at the first peripheral edge alignedwith at least one second recessed portion at the second peripheral edgeof the second separator sheet; and an electrolyte disposed between theanode and the cathode subassembly, wherein the first and secondperipheral edges respectively of the first and second separator sheetsare aligned with a peripheral edge of the anode; wherein the cathodeincludes a cathode tail that extends through the sealing region, aperipheral edge of the cathode includes multiple third recessed portionsand the sealing region is positioned in an interior of each of the thirdrecessed portions, and the tail is positioned between two of the thirdrecessed portions; and wherein another one of the third recessedportions is positioned on a side of the peripheral edge of the cathodethat is opposite from the two third recessed portions.
 19. A device,comprising: a conductive anode; a dielectric material disposed on asurface of the conductive anode; a cathode subassembly, wherein thecathode subassembly includes: a first separator sheet including asurface having a first region and a second region, wherein the secondregion extends from a perimeter of the first region to a firstperipheral edge of the first separator sheet; a cathode; and a secondseparator sheet having a second peripheral edge, wherein the secondperipheral edge is substantially aligned with the first peripheral edge,and wherein the cathode is sandwiched between the first and secondseparator sheets and disposed within the first region, and wherein thefirst and second separator sheets are adhered to each other in a sealingregion extending from the second region of the first separator sheet toa region of a surface of the second separator sheet facing the secondregion, and wherein the first separator sheet includes at least onefirst recessed portion at the first peripheral edge aligned with atleast one second recessed portion at the second peripheral edge of thesecond separator sheet; and an electrolyte disposed between the anodeand the cathode subassembly, wherein the first and second peripheraledges respectively of the first and second separator sheets are alignedwith a peripheral edge of the anode; wherein the cathode includes acathode tail that extends through the sealing region, a peripheral edgeof the cathode includes a third recessed portion and the sealing regionis positioned in an interior of the third recessed portion, and thethird recessed portion is positioned on a side of the peripheral edge ofthe cathode that is opposite from the cathode tail.
 20. The device ofclaim 19, wherein the first recessed portion and the second recessedportion are received in the third recessed portion.